"If Fred Thompson formally declares his intention to run for president, NBC will not schedule any further repeats of 'Law & Order' featuring Mr. Thompson beyond those already scheduled, which conclude on Saturday, Sept. 1," Wolf said.

Wolf assured that NBC would take all "appropriate steps consistent with FCC regulations."

Thompson fans would, however, be able to see him in reruns airing on TNT.

Thompson played D.A. Arthur Branch on the show for five years.

If Thompson is legally declared a candidate, and NBC airs episodes that feature 10 minutes of him, under the equal-time requirement the network would then have to feature all the other Republican candidates for an equal 10 minutes in some shape or form.

Political issues aside, "Law & Order" faced a major casting overhaul as it geared up for its 18th season.

Wolf said he recognized the shakeup as an opportunity to start skewing toward a younger audience.

To that end, Jeremy Sisto will replace Milena Govich as a detective and Linus Roache will step into Sam Waterson's prosecutor position as Waterson moves into Thompson's former slot as D.A.

"That is a very large shift and also a very deliberate shift to hopefully reignite or further attract a younger demo," said Wolf.

And Waterson's new role is part of changing the show.

"Sam is not going to be the pragmatist the elected politicians have been," Wolf said.

"He's also going to be someone who goes through changes in his own attitude because he is doing a different job, and a lot of it is going to be fascinating because we talked openly about what happens to men of a certain age and a certain stature when the next generation comes in. There's a lot to play here."

The only open-ended question remaining concerns Jesse L. Martin, who has been a regular on "Law & Order" since 1999. Martin is confirmed for only 13 of 22 episodes of the new season.

"Jesse could stay on for the entire season," said Wolf. "It's all up in the air. ... To try to tell you now what's going to happen in six months, I don't know."